Your strategy, even for a Biden voter like myself, seems extremist.
Democratic Senator Reed helped eliminate the filibuster on most judicial nominees in 2013.
Republican Senator McConnell finished the job and eliminated the filibuster on Supreme Court nominees in 2017.
I would rather see a group of moderate senators on both the Republican and Democratic side come together and return the filibuster to all nominees than to see what you propose above.
Besides, I wouldn't count PR as being solidly Democratic or even Washington D.C. as it gets whiter and less likely to vote Democratic. Not to mention that if you choose to go the route of expanding the Supreme Court to achieve some sort of ideological win, then when Republicans are next in power they too can enact all sorts of court packing schemes.
True reform needs to find a compromise rather than continued escalation. We need to draw back and explore ideas like term limits for Supreme Court justices. Removing the Senate from the confirmation role. 18 year terms so that each 4 years 1 new nominee goes on the Supreme Court. Things that will allow our democracy to flourish and our Supreme Court to not be viewed through a partisan lens.